{"product_id":"ultrasound-a-key-tool-for-preventing-strokes-and-heart-attacks","title":"Ultrasound: A Key Tool for Preventing Strokes and Heart Attacks","description":"\u003cp\u003eUltrasound is a powerful, radiation-free tool that can do far more than take pictures of unborn babies—it can help prevent strokes by measuring plaque buildup in the carotid arteries, identifying dangerous plaques, and detecting blood clots traveling to the brain. This review article by Dr. J. David Spence explains how measuring carotid plaque burden (the total amount of plaque in the arteries of the neck) is a far stronger predictor of heart attack and stroke risk than traditional measurements like intima-media thickness. Remarkably, a treatment approach called \"treating arteries instead of treating risk factors\" reduced stroke and heart attack risk by more than 80% over 2 years in high-risk patients. The article also covers how ultrasound can detect microemboli (tiny blood clots) that predict a 15.6% one-year stroke risk versus only 1% without them, and how it outperforms other methods for detecting patent foramen ovale (a heart defect linked to stroke).\u003c\/p\u003e\n\n\u003ch1\u003eUltrasound: A Key Tool for Preventing Strokes and Heart Attacks\u003c\/h1\u003e\n\n\u003ch2\u003eTable of Contents\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\u003ca href=\"#ddn-key-points\"\u003eKey Points\u003c\/a\u003e\u003c\/li\u003e\n\n  \u003cli\u003e\u003ca href=\"#background\"\u003eWhy This Research Matters\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#imt-vs-plaque\"\u003eThe Problem with Traditional Ultrasound Measurements\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#total-plaque-area\"\u003eTotal Plaque Area: A Better Measurement\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#treating-arteries\"\u003eTreating Arteries Instead of Risk Factors\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#unexplained-atherosclerosis\"\u003eWhy Some Patients Don't Respond to Treatment\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#3d-ultrasound\"\u003e3D Ultrasound: Plaque Volume and Vessel Wall Volume\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#vulnerable-plaque\"\u003eIdentifying Dangerous Plaques\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#tcd\"\u003eTranscranial Doppler: Detecting Clots and Heart Defects\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#clinical-implications\"\u003eWhat This Means for Patients\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#limitations\"\u003eStudy Limitations\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#recommendations\"\u003eRecommendations for Patients\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#ddn-faq\"\u003eFrequently Asked Questions\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#source\"\u003eSource Information\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003c!-- ddn:keypoints:start --\u003e\n\u003ch2 id=\"ddn-key-points\"\u003eKey Points\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eCarotid plaque burden measured by ultrasound predicts heart attack and stroke risk far better than intima-media thickness (IMT).\u003c\/li\u003e\n\u003cli\u003eA 'treating arteries' approach reduced 2-year stroke and heart attack risk by more than 80% in high-risk patients.\u003c\/li\u003e\n\u003cli\u003eUltrasound can identify dangerous plaque features like echolucency and ulceration, which raise stroke risk significantly.\u003c\/li\u003e\n\u003cli\u003eTranscranial Doppler detects microemboli in carotid stenosis, identifying a 15.6% one-year stroke risk versus 1% without.\u003c\/li\u003e\n\u003cli\u003eGut-derived toxins like TMAO may explain plaque progression despite low LDL, suggesting diet changes could help.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- ddn:keypoints:end --\u003e\n\n\n\u003ch2 id=\"background\"\u003eWhy This Research Matters\u003c\/h2\u003e\n\u003cp\u003eStroke remains one of the leading causes of death and disability worldwide, and its burden is growing as our populations age. This review article, written by a leading expert in stroke prevention, makes the case that ultrasound—a safe, inexpensive, and widely available imaging technology—is underused in the fight against stroke.\u003c\/p\u003e\n\n\u003cp\u003eMost people think of ultrasound as the technology used to see a baby during pregnancy. But ultrasound has many other medical uses, including looking at the carotid arteries in the neck, which supply blood to the brain. When these arteries become narrowed or blocked by a buildup of fatty deposits called plaque, a stroke can result. The good news is that ultrasound can detect this plaque early, measure it precisely, and even help doctors decide which patients need aggressive treatment.\u003c\/p\u003e\n\n\u003cp\u003eThe article describes multiple ways ultrasound can be used in stroke prevention, including measuring plaque burden (how much plaque is present), assessing plaque vulnerability (how dangerous the plaque is), and detecting microemboli (tiny blood clots that travel to the brain). Each of these uses is backed by specific research findings, which are detailed below.\u003c\/p\u003e\n\n\u003ch2 id=\"imt-vs-plaque\"\u003eThe Problem with Traditional Ultrasound Measurements\u003c\/h2\u003e\n\u003cp\u003eFor decades, doctors have used a measurement called intima-media thickness (IMT) to assess \"preclinical atherosclerosis\" (early hardening and narrowing of the arteries). IMT measures the thickness of the inner two layers of the artery wall. However, this review argues that a widespread misconception has developed: IMT does not actually represent true atherosclerosis.\u003c\/p\u003e\n\n\u003cp\u003eAccording to the Mannheim consensus (an international agreement on how to measure IMT), IMT is a biologically, pathologically, and genetically distinct condition from atherosclerosis. The article is blunt on this point: \u003cstrong\u003e\"This widespread delusion, that IMT represents 'preclinical atherosclerosis', should not be permitted to continue.\"\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eSome studies that appear to show IMT predicting cardiovascular risk actually combined plaque thickness with IMT in their measurements, which conflates patients with plaque and patients without plaque. When measured strictly according to the Mannheim consensus standards, IMT is only a weak—or even non-existent—predictor of risk. Furthermore, the progression of IMT over time does not predict risk of heart attacks or strokes. This is a critical distinction, because an inaccurate measurement can lead to either unnecessary worry or false reassurance.\u003c\/p\u003e\n\n\u003ch2 id=\"total-plaque-area\"\u003eTotal Plaque Area: A Much Stronger Measurement\u003c\/h2\u003e\n\u003cp\u003eInstead of measuring artery wall thickness, Dr. Spence's team has championed a different approach: measuring the total plaque area (TPA). This is done by tracing the outline of each plaque seen on ultrasound in the plane where it is biggest. All plaques on both sides of the neck, from the collarbone (clavicle) to the angle of the jaw, are measured, and the sum of all the plaque areas gives the total plaque area.\u003c\/p\u003e\n\n\u003cp\u003eThis measurement is remarkably simple to perform. It can be taught to any experienced ultrasound technologist in a day, and it is highly reliable: the intraclass correlation for repeat measurements is 0.94, meaning the results are very consistent when the same patient is measured twice. The method was invented in Dr. Spence's lab in 1986 by Maria DiCicco, a registered vascular technologist.\u003c\/p\u003e\n\n\u003cp\u003eStarting in 1995, the team began measuring TPA routinely in their vascular prevention clinics. By 2002, they had strong evidence that TPA predicts cardiovascular risk far better than traditional risk scores. Here are the key numbers from their research:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003ePatients were divided into four groups (quartiles) based on their plaque area.\u003c\/li\u003e\n  \u003cli\u003eThe 5-year risk of stroke, heart attack, or vascular death was \u003cstrong\u003e5.6%\u003c\/strong\u003e for the lowest quartile, \u003cstrong\u003e10.7%\u003c\/strong\u003e for the second, \u003cstrong\u003e13.9%\u003c\/strong\u003e for the third, and \u003cstrong\u003e19.5%\u003c\/strong\u003e for the highest quartile.\u003c\/li\u003e\n  \u003cli\u003eThese results were calculated after adjusting for age, sex, blood pressure, serum cholesterol, smoking (pack-years), diabetes, plasma total homocysteine, and treatment of blood pressure and cholesterol.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eIn other words, a patient in the highest quartile of plaque area had more than three times the risk of a patient in the lowest quartile. This was a much stronger prediction than the well-known Framingham risk score, which estimates risk based on traditional risk factors alone.\u003c\/p\u003e\n\n\u003cp\u003eCarotid plaque burden also correlates highly with coronary calcium scores—another strong predictor of heart risk—but ultrasound has two major advantages: it costs less and it does not expose patients to radiation. Additionally, plaque progression was found to occur in half the patients despite usual therapy. Patients whose plaque progressed had \u003cstrong\u003etwice the risk\u003c\/strong\u003e of those with stable plaque or regression. Regression (shrinkage) of plaque occurred in only 25% of patients. This was a wake-up call: usual therapy was failing half their patients.\u003c\/p\u003e\n\n\u003ch2 id=\"treating-arteries\"\u003eTreating Arteries Instead of Treating Risk Factors\u003c\/h2\u003e\n\u003cp\u003eIn 2003, Dr. Spence's clinic implemented a completely new approach to vascular prevention. Instead of being satisfied with reaching target levels of risk factors like blood pressure and LDL cholesterol (the \"bad\" cholesterol), the new goal was to stop plaque progression or even achieve plaque regression. The concept can be summarized simply: \u003cstrong\u003e\"Treating arteries without measuring plaque would be like treating hypertension without measuring blood pressure.\"\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eThe results were dramatic. By 2010, it was clear that this approach had markedly reduced the risk of patients with asymptomatic carotid stenosis (ACS)—a condition where the carotid arteries are narrowed but the patient has not yet had symptoms like a stroke or transient ischemic attack (a \"mini-stroke\"). The proportion of patients whose plaque regressed versus progressed had reversed: now only about a quarter had plaque progression, while about half had regression.\u003c\/p\u003e\n\n\u003cp\u003eAdditional improvements observed after implementing this approach:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eThe percentage of patients with microemboli on transcranial Doppler (a strong predictor of risk, discussed below) declined from \u003cstrong\u003e12.6% to 3.7%\u003c\/strong\u003e.\u003c\/li\u003e\n  \u003cli\u003eThe rate of carotid plaque progression declined significantly.\u003c\/li\u003e\n  \u003cli\u003eThe 2-year risk of stroke and heart attack declined by \u003cstrong\u003emore than 80%\u003c\/strong\u003e.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eThis quote from the article underscores the practical impact: \"After implementing 'treating arteries'... the 2-year risk of stroke and myocardial infarction declined by more than 80%.\" Plaque changes can be seen within a clinically meaningful timeframe—sometimes even within 3 months, as demonstrated by a case where a patient's plaque area regressed from 28 mm² back to 19 mm² in 13 weeks after adjusting his medication regimen.\u003c\/p\u003e\n\n\u003ch2 id=\"unexplained-atherosclerosis\"\u003eWhy Some Patients Don't Respond to Treatment: The Gut Microbiome Connection\u003c\/h2\u003e\n\u003cp\u003eAfter treating more than 4,000 patients with the \"treating arteries\" approach, researchers noticed something important: some patients had atherosclerosis that could not be explained by traditional risk factors. These patients were extraordinarily resistant to even intensive medical therapy. Neither their baseline LDL cholesterol levels nor the change in LDL cholesterol over a year predicted whether their plaque would progress or regress.\u003c\/p\u003e\n\n\u003cp\u003eEven among patients with LDL cholesterol below 1 mmol\/L (19 mg\/dL)—an extremely low level by any standard—half still had plaque progression. Interestingly, the researchers noted these were often the patients being treated most intensively, suggesting their atherosclerosis was driven by factors other than cholesterol. Two factors that did predict resistance to therapy were \u003cstrong\u003eage\u003c\/strong\u003e and \u003cstrong\u003erenal function\u003c\/strong\u003e (kidney function). This led to a key hypothesis: metabolic toxins that are normally excreted by the kidneys may account for a substantial proportion of \"unexplained atherosclerosis.\"\u003c\/p\u003e\n\n\u003cp\u003ePatients with renal failure have extremely high cardiovascular risk. They have high blood levels of several toxins, including homocysteine, asymmetric dimethylarginine (ADMA, which blocks nitric oxide—a molecule that relaxes blood vessels), thiocyanate (a potent factor increasing oxidative stress), and toxic metabolites produced by the intestinal microbiome from dietary precursors such as carnitine (found in red meat) and phosphatidylcholine (found in egg yolk).\u003c\/p\u003e\n\n\u003cp\u003eIn 2016, researchers estimated that plasma total homocysteine only accounted for about 20% of the effect of renal impairment on atherosclerosis. They hypothesized that toxic metabolites from the gut microbiome might account for a larger share. In 2018, they reported a groundbreaking finding:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003ePlasma levels of \u003cstrong\u003etrimethylamine N-oxide (TMAO)\u003c\/strong\u003e, \u003cstrong\u003ep-cresyl sulfate\u003c\/strong\u003e, and two other metabolites were significantly higher in patients with unexplained atherosclerosis (those with more plaque than predicted by risk factors) compared to patients whose atherosclerosis was explained by traditional risk factors.\u003c\/li\u003e\n  \u003cli\u003eThese same metabolites were significantly \u003cstrong\u003elower\u003c\/strong\u003e in \"protected\" patients—those with little or no plaque despite having high levels of traditional risk factors.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eThe differences were striking. For TMAO, the P value was 0.005; for p-cresyl sulfate, P was 0.0001. In statistical terms, a P value below 0.05 means the result is very unlikely to be due to chance, and a value of 0.0001 means there is only a 0.01% chance the finding is random. Additional metabolites—p-cresyl glucuronide and phenylacetyl glutamine—also showed highly significant differences (P=0.0001 for both).\u003c\/p\u003e\n\n\u003cp\u003eIn a linear regression model, both TMAO and p-cresyl sulfate were significant predictors of plaque burden, even when other factors like sex, diabetes, serum cholesterol, and diastolic blood pressure were excluded from the model. This research points to a fascinating possibility: changing the diet (to reduce production of these gut-derived toxins) could be a new way to prevent heart disease and stroke in patients who don't respond to standard treatments.\u003c\/p\u003e\n\n\u003ch2 id=\"3d-ultrasound\"\u003e3D Ultrasound: Measuring Plaque Volume and Vessel Wall Volume\u003c\/h2\u003e\n\u003cp\u003eWhile 2D ultrasound measures plaque area, 3D ultrasound takes things further by measuring total plaque volume (TPV) and vessel wall volume (VWV). These methods, developed by Dr. Fenster and colleagues, involve manual segmentation of cross-sectional slices of plaques—a process that is quite tedious and requires significant training. It takes several months to become certified to do the measurements reliably, and about a third of people simply cannot perform them well (some are too perfectionist and cannot make decisions about boundaries, while others are too careless).\u003c\/p\u003e\n\n\u003cp\u003eHowever, measuring changes in 3D plaque volume is \u003cstrong\u003ethe most efficient way\u003c\/strong\u003e to assess the effects of therapy on atherosclerosis. Here's why other methods fall short:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eIMT changes by only about 1.5 mm per year, and the spatial resolution of carotid ultrasound is about 3 mm. This means it's impossible to measure a change in IMT within an individual in a clinically meaningful timeframe.\u003c\/li\u003e\n  \u003cli\u003eConsensus sample sizes for IMT studies of anti-atherosclerotic therapies are about \u003cstrong\u003e300 patients per group\u003c\/strong\u003e, followed for \u003cstrong\u003e2 years\u003c\/strong\u003e.\u003c\/li\u003e\n  \u003cli\u003eIntravascular ultrasound (IVUS) studies, which examine coronary arteries, require about \u003cstrong\u003e200 patients per group\u003c\/strong\u003e followed for 2 years. Because coronary plaques are present throughout the length of the imaging pullback, the change measurement reduces to a single dimension: average plaque thickness.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eCarotid plaques, in contrast, are focal (they occur in distinct spots), so they can change in three dimensions: length, thickness, and circumferential extent. This means \u003cstrong\u003esample sizes and study durations can be much smaller\u003c\/strong\u003e for 3D plaque volume studies than for other methods.\u003c\/p\u003e\n\n\u003cp\u003eA striking demonstration of this efficiency was published in 2002. In a study of patients with asymptomatic carotid stenosis, researchers found a significant reduction of plaque volume with atorvastatin (a statin drug) compared to placebo in \u003cstrong\u003eonly 3 months\u003c\/strong\u003e, with just \u003cstrong\u003e17 patients randomized to placebo and 21 to atorvastatin\u003c\/strong\u003e. The results were dramatic:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eCarotid plaque volume \u003cstrong\u003eprogressed by +16.81 ± 74.10 mm³\u003c\/strong\u003e in patients taking placebo.\u003c\/li\u003e\n  \u003cli\u003ePatients taking atorvastatin showed \u003cstrong\u003eregression of −90.25 ± 85.12 mm³\u003c\/strong\u003e.\u003c\/li\u003e\n  \u003cli\u003eThe difference was highly statistically significant (P\u0026lt;0.0001).\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eFor patients who do not yet have carotid plaque, 3D ultrasound measurement of vessel wall volume (VWV) is superior to IMT because the dynamic range is much greater and the ability to detect change over time is far superior. In a dietary study with only 140 participants, blood pressure reduction with weight loss was strongly associated with reduced VWV over 2 years—a result that would have required a much larger study using IMT.\u003c\/p\u003e\n\n\u003ch2 id=\"vulnerable-plaque\"\u003eIdentifying Dangerous Plaques: Echolucency, Ulceration, and Texture\u003c\/h2\u003e\n\u003cp\u003eNot all plaque is equally dangerous. Some plaques are stable and unlikely to cause problems, while others are \"vulnerable\" and prone to rupture, leading to stroke. When a patient has asymptomatic carotid stenosis (ACS), the overall risk of stroke is now lower with intensive medical therapy than with either stenting or surgical endarterectomy. Therefore, it is crucial to identify the \u003cstrong\u003efew patients (perhaps 10–15%)\u003c\/strong\u003e who would actually benefit from invasive intervention. Ultrasound offers several ways to spot these high-risk patients.\u003c\/p\u003e\n\n\u003ch3\u003eEcholucency: The \"Black\" Plaque Danger Sign\u003c\/h3\u003e\n\u003cp\u003eOn an ultrasound image, some plaques appear dark (\"echolucent\") because they contain soft material like thrombus (blood clot) or lipid (fat). Plaques that are echolucent—especially those with a large \u003cstrong\u003ejuxtaluminal black area (JBA)\u003c\/strong\u003e, a black area right next to the artery opening—carry a higher risk of stroke.\u003c\/p\u003e\n\u003cp\u003eDr. Nicolaides and colleagues studied 324 patients with 50–99% carotid stenosis. They found that two features in particular were independent predictors of having had hemispheric symptoms (symptoms affecting one side of the brain):\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eStenosis gray scale median (GSM) ≤ 15 (meaning the plaque was very dark on ultrasound)\u003c\/li\u003e\n  \u003cli\u003eJBA ≥ 8 mm² (a large black area adjacent to the artery lumen)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eThis combination identified a high-risk group with an \u003cstrong\u003eodds ratio (OR) of 6.7\u003c\/strong\u003e (95% confidence interval: 4.08–10.91, P\u0026lt;0.001). In plain language, patients with these ultrasound features were \u003cstrong\u003enearly 7 times more likely\u003c\/strong\u003e to have had symptoms related to their carotid disease. Additionally, Dr. Markus and colleagues found that the combination of echolucency with microemboli on transcranial Doppler was linked to a marked increase in stroke risk.\u003c\/p\u003e\n\n\u003ch3\u003eUlceration: Craters in the Plaque\u003c\/h3\u003e\n\u003cp\u003ePlaque ulcers are crater-like breaks in the surface of the plaque. These are dangerous because they expose the inner contents of the plaque to the bloodstream, which can trigger clot formation. The North American Symptomatic Carotid Endarterectomy (NASCET) Study showed that plaque ulceration detected by angiography predicted a higher risk of stroke. However, angiograms only show the lumen (the inside channel of the artery). The best way to assess carotid ulceration is by \u003cstrong\u003e3D ultrasound\u003c\/strong\u003e, which can visualize the plaque surface in detail.\u003c\/p\u003e\n\u003cp\u003eIn 2011, Dr. Spence's team reported important findings about ulcers:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003ePatients with \u003cstrong\u003e3 or more ulcers\u003c\/strong\u003e in either or both carotid arteries had a risk very similar to that of patients with microemboli on TCD.\u003c\/li\u003e\n  \u003cli\u003e4% of patients had ≥3 ulcers, 6% had microemboli, and 10% had either microemboli or ≥3 ulcers.\u003c\/li\u003e\n  \u003cli\u003ePatients with 3 or more ulcers in either carotid were significantly more likely to have a stroke or death within 3 years: \u003cstrong\u003e18% versus 2% (P=0.03)\u003c\/strong\u003e, regardless of which side the ulcers were on.\u003c\/li\u003e\n  \u003cli\u003eThe 3-year risk of stroke or death was \u003cstrong\u003e20% with microemboli versus 2% without (P\u0026lt;0.003)\u003c\/strong\u003e.\u003c\/li\u003e\n  \u003cli\u003eThe annual rate of stroke on the same side as the carotid disease was only 0.8%—a reminder that while the overall risk is low, it is concentrated in identifiable high-risk subgroups.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eIn 2014, the team went a step further and assessed ulcer volume as a predictor of risk. Among 349 patients followed for 5 years, those with a total ulcer volume of ≥5 mm³ had a significantly higher risk of stroke, transient ischemic attack (TIA or \"mini-stroke\"), or death (P=0.009), and also a higher risk of the combined endpoint of stroke\/TIA\/death\/heart attack\/revascularization (P=0.017).\u003c\/p\u003e\n\n\u003ch3\u003ePlaque Texture: A Window into Plaque Composition\u003c\/h3\u003e\n\u003cp\u003eAn emerging field in ultrasound research is the analysis of plaque texture using computer processing of the radiofrequency signals from carotid ultrasound. These complex mathematical analyses assess the distribution of pixel intensities within plaques, yielding texture parameters such as coarseness or contrast.\u003c\/p\u003e\n\n\u003cp\u003eResearch has shown that these texture measures can differentiate between symptomatic and asymptomatic patients, and they were actually \u003cstrong\u003esuperior to assessment of plaque shape\u003c\/strong\u003e. They also predicted cardiovascular events better than a combination of a history of events and traditional plaque features like plaque area and gray scale median.\u003c\/p\u003e\n\n\u003cp\u003eIn 2014, researchers evaluated 298 patients with carotid atherosclerosis using 3D ultrasound at baseline and again after 1 year. They measured carotid plaque volume and 376 measures of plaque texture, then followed patients for up to 5 years (median follow-up of 3.12 years, range 0.77–4.66 years) for heart attacks, TIAs, and strokes. The results were clear:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eChanges in plaque texture combined with total plaque volume provided the \u003cstrong\u003ebest predictor of vascular events\u003c\/strong\u003e.\u003c\/li\u003e\n  \u003cli\u003eIn multivariate Cox regression analysis, changes in plaque texture (median hazard ratio 1.4, P\u0026lt;0.001) and total plaque volume (median hazard ratio 1.5 per 100 mm³, P\u0026lt;0.001) were both significant predictors.\u003c\/li\u003e\n  \u003cli\u003eThe Framingham risk score, by contrast, was \u003cstrong\u003enot\u003c\/strong\u003e a significant predictor in this model.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eA hazard ratio of 1.4 means that for each unit increase in the texture change measure, the risk of an event increased by 40%. Similarly, each 100 mm³ increase in plaque volume increased risk by 50%. The fact that these ultrasound-based measures outperformed the well-established Framingham risk score is remarkable.\u003c\/p\u003e\n\n\u003ch2 id=\"tcd\"\u003eTranscranial Doppler: Detecting Clots and Heart Defects\u003c\/h2\u003e\n\u003cp\u003eTranscranial Doppler (TCD) is a special type of ultrasound that uses sound waves to measure blood flow in the brain's blood vessels. It has three main uses in stroke prevention: assessing intracranial stenosis (narrowing of arteries inside the brain), detecting microemboli in patients with carotid stenosis, and detecting patent foramen ovale (PFO).\u003c\/p\u003e\n\n\u003ch3\u003eTCD Embolus Detection: Finding the \"Smoking Gun\" Microemboli\u003c\/h3\u003e\n\u003cp\u003eDetection of microemboli—tiny particles or blood clots traveling in the bloodstream to the brain—is perhaps the best-validated way to identify which patients with asymptomatic carotid stenosis are at high risk. Microemboli show up as distinctive high-intensity transient signals on the TCD display, often accompanied by a characteristic clicking sound.\u003c\/p\u003e\n\n\u003cp\u003eIn 2005, researchers reported on 319 patients with asymptomatic carotid stenosis. The findings were striking:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003e10% of patients\u003c\/strong\u003e had two or more microemboli detected during one hour of monitoring.\u003c\/li\u003e\n  \u003cli\u003eThese patients had a \u003cstrong\u003e1-year risk of stroke of 15.6%\u003c\/strong\u003e.\u003c\/li\u003e\n  \u003cli\u003ePatients without microemboli had a 1-year risk of only \u003cstrong\u003e1%\u003c\/strong\u003e.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eThis is a 15-fold difference in risk, making TCD embolus detection an extraordinarily powerful tool for risk stratification. The clinical implications are direct: patients with microemboli could benefit from interventions such as carotid endarterectomy (surgical removal of plaque) or stenting, which carry periprocedural risks of stroke or death of about 3–4%. Patients without microemboli, however, would be better treated with intensive medical therapy alone, since their low risk does not justify the risks of surgery.\u003c\/p\u003e\n\n\u003cp\u003eIn 2010, researchers reported on 468 patients (199 enrolled before 2003 and 269 after 2003) and confirmed that intensive medical therapy reduced the percentage of patients with microemboli, as described in the \"treating arteries\" approach above.\u003c\/p\u003e\n\n\u003ch3\u003eTCD Saline Studies: A Better Way to Detect PFO\u003c\/h3\u003e\n\u003cp\u003eA patent foramen ovale (PFO) is a small flap-like opening between the upper chambers of the heart that fails to close completely after birth. In some people, this opening can allow blood clots to pass from the right side of the heart to the left side, bypassing the lungs' filtering system. This is called \u003cstrong\u003eparadoxical embolism\u003c\/strong\u003e—a clot that takes a \"wrong turn\" and goes to the brain instead of the lungs, causing a stroke.\u003c\/p\u003e\n\n\u003cp\u003eEven among patients with cryptogenic stroke (a stroke with no clearly determined cause), \u003cstrong\u003eapproximately half of PFOs are incidental\u003c\/strong\u003e, meaning they exist coincidentally without causing the stroke. This makes it difficult to determine whether a PFO was the actual cause of a stroke or just a bystander. Therefore, it is important to have ways to identify those patients most likely to benefit from PFO closure procedures.\u003c\/p\u003e\n\n\u003cp\u003eClinical clues that a stroke may be due to paradoxical embolism include:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eProlonged sitting (which increases the risk of blood clots in the legs)\u003c\/li\u003e\n  \u003cli\u003eDyspnea (shortness of breath) at the onset of stroke\u003c\/li\u003e\n  \u003cli\u003eLow oxygen (pO₂) and carbon dioxide (pCO₂) levels in the blood at the time of the stroke\u003c\/li\u003e\n  \u003cli\u003eA previous history of deep vein thrombosis (blood clot in the leg)\u003c\/li\u003e\n  \u003cli\u003eA history of pulmonary embolism (blood clot in the lungs) or varicose veins\u003c\/li\u003e\n  \u003cli\u003eA history of sleep apnea\u003c\/li\u003e\n  \u003cli\u003eWaking up with stroke symptoms (likely related to sleep apnea)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eAlthough transesophageal echocardiography (TEE)—an ultrasound performed through the esophagus—is often regarded as the gold standard for diagnosing PFO, the article makes an important claim: \u003cstrong\u003eTCD saline studies are actually more sensitive for detecting PFO\u003c\/strong\u003e, and the size of the right-to-left shunt (RLS) as measured by TCD is \u003cstrong\u003emore predictive of recurrent stroke\u003c\/strong\u003e than the mere presence of a PFO on TEE. This is because TCD can quantify how much blood shunts through the PFO, not just whether a PFO exists.\u003c\/p\u003e\n\n\u003ch2 id=\"clinical-implications\"\u003eWhat This Means for Patients\u003c\/h2\u003e\n\u003cp\u003eThe research summarized in this article has several practical implications for patients at risk of stroke:\u003c\/p\u003e\n\u003col\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAsk about plaque burden measurement.\u003c\/strong\u003e If you have risk factors for stroke or heart disease, ask your doctor whether measuring your carotid plaque burden (rather than just IMT) would help clarify your risk. Plaque area and plaque volume are much stronger predictors than IMT.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAggressive treatment can reverse plaque.\u003c\/strong\u003e The \"treating arteries\" approach shows that with intensive medical therapy—including statins and blood pressure control—plaque can actually shrink over a period of months. This is motivating news: your arteries can get better, not just stop getting worse.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eThe gut microbiome matters.\u003c\/strong\u003e The connection between gut bacteria and atherosclerosis is still emerging, but the research suggests that diet may play a role beyond just cholesterol. Metabolites from red meat (carnitine) and egg yolk (phosphatidylcholine) are processed by gut bacteria into TMAO, which appears to promote atherosclerosis. This may be especially important for patients whose atherosclerosis progresses despite very low LDL cholesterol levels.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eNot all carotid stenosis requires surgery.\u003c\/strong\u003e With modern intensive medical therapy, the overall risk of asymptomatic carotid stenosis is low (annual ipsilateral stroke rate of 0.8%). TCD embolus detection and plaque assessment can identify the small minority of patients who actually need stenting or surgery.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePFO detection is nuanced.\u003c\/strong\u003e If you've had a cryptogenic stroke and are being evaluated for PFO, ask whether TCD saline studies are being considered. They may provide a more sensitive assessment than TEE alone, and the size of the shunt is an important factor in deciding whether to close the PFO.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch2 id=\"limitations\"\u003eWhat This Study Couldn't Prove\u003c\/h2\u003e\n\u003cp\u003eIt's important to note that this is a \u003cem\u003enarrative review article\u003c\/em\u003e, meaning it is a summary and interpretation of many studies by a single expert author, not a new clinical trial itself. Some limitations to keep in mind:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eThe \"treating arteries\" approach was implemented in a single specialized clinic (though it has been adopted more widely since). The \u0026gt;80% reduction in stroke and heart attack risk was observed in this clinical setting and may not be fully reproducible in other settings with different patient populations or resources.\u003c\/li\u003e\n  \u003cli\u003eThe connections between gut microbiome metabolites and atherosclerosis are observational. While the association between TMAO and plaque burden is statistically strong, this does not prove that TMAO directly causes atherosclerosis. Clinical trials are needed to show that reducing these metabolites actually reduces cardiovascular events.\u003c\/li\u003e\n  \u003cli\u003e3D plaque volume measurement is technically demanding and cannot be performed reliably by about a third of people attempting it, which limits its widespread adoption.\u003c\/li\u003e\n  \u003cli\u003eThe article was written by a single author who is clearly a strong proponent of these ultrasound methods, which introduces potential bias in the interpretation of the literature.\u003c\/li\u003e\n  \u003cli\u003eThe text mentions that the full discussion of TCD's role in other applications was cut off in the provided text (\"however, even...\" appears to be truncated), so some details may be missing from this patient summary.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2 id=\"recommendations\"\u003eRecommendations for Patients\u003c\/h2\u003e\n\u003cp\u003eBased on this research, here are actionable steps for patients concerned about stroke prevention:\u003c\/p\u003e\n\u003col\u003e\n  \u003cli\u003e\n\u003cstrong\u003eKnow your numbers.\u003c\/strong\u003e In addition to blood pressure and cholesterol, ask about your carotid plaque burden if you have risk factors. Plaque area and volume tell you more about your actual arterial health than cholesterol levels alone.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAsk about follow-up imaging.\u003c\/strong\u003e If you have carotid plaque, ask about repeat ultrasound to see whether your plaque is progressing, stable, or regressing on your current treatment. This allows your doctor to adjust treatment based on your actual response, rather than just checking laboratory values.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eConsider TCD testing.\u003c\/strong\u003e If you have asymptomatic carotid stenosis, ask whether transcranial Doppler embolus detection should be part of your evaluation. The 15-fold difference in stroke risk between those with and without microemboli is one of the most powerful risk stratification tools available.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBe proactive about diet.\u003c\/strong\u003e While the gut microbiome research is evolving, there is growing evidence that reducing red meat consumption (especially with high carnitine content) and being mindful of dietary sources of TMAO precursors may be beneficial for arterial health. This is in line with general cardiovascular dietary advice: a plant-forward, Mediterranean-style diet is wise.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTreat the artery, not just the numbers.\u003c\/strong\u003e Work with your healthcare team to agree on treatment goals that include not just blood pressure and cholesterol targets, but also the goal of stabilizing or reducing your plaque burden, as measured by ultrasound.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAsk about PFO evaluation after cryptogenic stroke.\u003c\/strong\u003e If you've had a stroke without an identified cause, ask whether a TCD saline study should be part of your workup, particularly if you have clues such as prolonged sitting, sleep apnea, or a history of blood clots.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003c!-- ddn:faq:start --\u003e\n\u003ch2 id=\"ddn-faq\"\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003ch3\u003eWhat is carotid plaque burden and why is it better than intima-media thickness (IMT)?\u003c\/h3\u003e\n\u003cp\u003eCarotid plaque burden is the total amount of plaque in your neck arteries, measured by ultrasound. It is a much stronger predictor of heart attack and stroke than IMT. In one study, patients with the highest plaque area had over three times the risk of the lowest group, even after adjusting for other risk factors.\u003c\/p\u003e\n\u003ch3\u003eWhat does 'treating arteries instead of treating risk factors' mean?\u003c\/h3\u003e\n\u003cp\u003eInstead of just aiming for target blood pressure and cholesterol levels, this approach uses ultrasound to track plaque progression. The goal is to stop plaque growth or even shrink it. In a specialized clinic, this strategy reduced the 2-year risk of stroke and heart attack by more than 80% in high-risk patients.\u003c\/p\u003e\n\u003ch3\u003eHow can ultrasound identify dangerous plaques that might cause a stroke?\u003c\/h3\u003e\n\u003cp\u003eUltrasound can spot dangerous features like echolucent (dark) plaques, large black areas near the artery opening, and ulcerations. In a study, patients with three or more ulcers in their carotid arteries had an 18% risk of stroke or death within 3 years, compared to 2% for those without.\u003c\/p\u003e\n\u003ch3\u003eWhat is transcranial Doppler (TCD) and how does it help assess stroke risk?\u003c\/h3\u003e\n\u003cp\u003eTCD uses sound waves to measure blood flow in the brain. It can detect microemboli, tiny blood clots traveling to the brain. In a study of 319 patients with asymptomatic carotid stenosis, those with microemboli had a 15.6% one-year stroke risk, compared to just 1% for those without.\u003c\/p\u003e\n\u003ch3\u003eWhat is a patent foramen ovale (PFO) and why is TCD saline testing recommended?\u003c\/h3\u003e\n\u003cp\u003eA PFO is a small opening between the heart's upper chambers that can let clots bypass the lungs and reach the brain, causing stroke. TCD saline studies are more sensitive for detecting PFO and can measure the shunt size, which better predicts recurrent stroke than just seeing a PFO on echocardiography.\u003c\/p\u003e\n\u003ch3\u003eHow does the gut microbiome affect plaque buildup and stroke risk?\u003c\/h3\u003e\n\u003cp\u003eGut bacteria process certain foods, like red meat and egg yolk, into toxins such as TMAO. Higher blood levels of these toxins were found in patients with unexplained atherosclerosis. This suggests diet might help prevent stroke, especially for patients whose plaque progresses despite very low LDL cholesterol.\u003c\/p\u003e\n\u003ch3\u003eWhat ultrasound tests should I ask my doctor about for stroke prevention?\u003c\/h3\u003e\n\u003cp\u003eIf you have risk factors, ask about measuring carotid plaque burden (area or volume) rather than only IMT. If you have carotid stenosis, ask about transcranial Doppler to check for microemboli. After a cryptogenic stroke, ask about TCD saline testing for PFO. These tests help guide personalized treatment.\u003c\/p\u003e\n\u003c!-- ddn:faq:end --\u003e\n\n\u003ch2 id=\"source\"\u003eSource Information\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eOriginal article title:\u003c\/strong\u003e Uses of ultrasound in stroke prevention\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor:\u003c\/strong\u003e J. David Spence, CM, MD, FRCPC, FAHA, Stroke Prevention \u0026amp; Atherosclerosis Research Centre, Robarts Research Institute, Western University, London, ON, Canada\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eJournal:\u003c\/strong\u003e Cardiovascular Diagnosis and Therapy, 2020;10(4):955-964. This article was part of a special series on Advanced Imaging in The Diagnosis of Cardiovascular Diseases.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003ePublication dates:\u003c\/strong\u003e Submitted Oct 22, 2019; Accepted Dec 09, 2019; published online August 2020.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDOI:\u003c\/strong\u003e 10.21037\/cdt.2019.12.12\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eNote:\u003c\/strong\u003e This patient-friendly article is based on peer-reviewed research. All statistics, percentages, and study findings included above are taken directly from the original publication. This educational summary is not a substitute for professional medical advice. Always consult your healthcare provider about your individual risk factors and treatment options.\u003c\/p\u003e","brand":"DiagnosticDetectives.Com","offers":[{"title":"Default Title","offer_id":47400025096348,"sku":null,"price":0.0,"currency_code":"CHF","in_stock":true}],"url":"https:\/\/diagnosticdetectives.ch\/products\/ultrasound-a-key-tool-for-preventing-strokes-and-heart-attacks","provider":"DiagnosticDetectives.Com","version":"1.0","type":"link"}